Subwoofer Suggestion

@Kulo:

El Pipe-O is a DIY sub. Quite a large variety of woofers can be used as drivers. I’m sure you could find a suitable pair locally. 

Well I'm not really looking for a diy sub, but if all else fails I'll give it a try thank you.

I bought 2 SVS sb2000 subs on sale for $650 each (price reduced when they brought out the sb2000 pro model).  They compliment my Martin Logan 60XT towers.  I set the crossover at 80HZ and let the subs handle frequencies below that.  Room placement is not optimized and I seldom play music real loud.   I’m not sure I have them dialed in correctly — read somewhere that mains show be set at 20 HZ and let the subs handle below that (?).  Don’t know if that advice works or not.

@bob540 may I know the size of your room?

@kulo 
What are you trying to achieve?  Is it to seamlessly fill in/extending the lower bass resisters while maintaining a cohesive fidelity or do you want the movie theater chest thumping experience?  These are 2 very different goals as the AudioKinesis Swarm seems to lean towards the former.